1. Field of the Invention
This document relates to a display apparatus, and more particularly, to a plasma display apparatus.
2. Description of the Background Art
Out of display apparatuses, a plasma display apparatus generally comprises a plasma display panel and a driver for driving the plasma display panel.
The plasma display panel comprises a front panel and a rear panel which are made of soda-lime glass. Barrier ribs formed between the front panel and the rear panel form discharge cells. Each of the discharge cells is filled with an inert gas such as a He—Xe gas mixture, a He—Ne gas mixture. When the inert gas is discharged by a high frequency voltage, vacuum ultraviolet rays are generated. Vacuum ultraviolet rays excites a phosphors formed between the barrier ribs to display an image on the plasma display panel.
The front panel comprises a transparent electrode and a bus electrode. A black layer is formed between the transparent electrode and the bus electrode. The black layer is formed of an electrically conductive material such as ruthenium oxide, lead oxide, carbon series. The black layer and a black matrix formed between maintenance electrode pairs improve the contrast between the discharge cells.
Since Ag forming the bus electrode does not transmit light generated by the discharge and reflects light generated from the outside of the plasma display panel, the contrast is degraded.
The black layer capable of improving the contrast is interposed between the transparent electrode and the bus electrode to overcome the above-described problem.
The black layer performs a light blocking function for reducing reflectivity by absorbing external light generated from the outside of a front glass substrate of the front panel, and improves color purity and the contrast of the front glass substrate.
However, since the width of the related art black layer is approximately equal to the width of the bus electrode, edge curl is easily generated in an edge of the bus electrode. A poor contact occurs where the bus electrode contacts the black layer. It is difficult to uniformly accumulate wall charges within the discharge cell. Further, the black layer insufficiently performs the light blocking function and insufficiently improves the color purity and the contrast.